1. Field of the Invention
The claimed invention relates to a new marine fender for absorption, deflection, or dissipation of kinetic impact energy that occurs when a waterborne vessel engages with a piling, dock, or other marine structure, and more specifically, relates to a marine fender suitable for a monopile, a dolphin, or open, over-water dock pilings. This invention also describes a method of assembly of a marine fender.
2. Description of Related Art
Monopiles and dolphins provide prime defense for piers and docks against runaway vessels. Monopiles and dolphins deflect ships and barges as they negotiate narrow waterways or hairpin turns. Monopiles and dolphins are also used for docking barges mid-channel for over-water loading and off-loading. The fender piles are known to be stiff and lack the capacity for large deflection which results in high reaction loads, resulting in vessel hull damage and frequent breakage of piling. Stacking used tires on monopiles is a known practice as they require no or little modification to the monopile. Tires are known for their poor shock absorbing properties; tires in the water swell, “roll up”, tear, and abrade, needing frequent replacement that is costly in time, labor, and permitting. Environmental agencies are banning the use of tires and rubber products in the water as they are a source of pollution. Therefore, a suitable alternative to used tires as fenders is sought. Prior art describes linkable fenders that resists separation and can conform to odd angles, such as around a bow of a boat. The joiner is connecting strips inserted into channels in the periphery of the fender. Linkable fenders that are pliable enough to deform with hand pressure to insert a connecting strip lack the capacity for large deflection of tens of thousands of tons at any speed. Other prior art use joiners like inflatable pneumatic sleeves or rope. Fenders joined with inflatable pneumatic sleeves can puncture and deflate. Fenders joined with ropes cannot hold in position in the wake of shipping traffic. Prior art discloses an apparatus for protecting a bridge pillar that uses pivoting elastic connectors to hold cushioning pads in position. This apparatus is too complex and expensive for a monopile and would require extensive retrofitting. Prior art discloses a shock absorbing open-ended cylindrical fender formed of polyurethane layers of different durometers. Polyurethane is toxic and current pollution prevention policies ban its use in the water. If the piling with such a fender needs repair, the fender would be costly and time consuming to remove and replace. Prior art discloses a modular bumper with attachment rail configured to either receive an associated molding that slides on or have the molding snap fit over the attachment rail. The attachment rail fixes the modular bumper into position in such a manner that the bumper would offer resistance upon impact, resulting in damage to the bumper, the piling and hull of the vessel. Prior art discloses a rotating hollow bumper assembly that can be split along one side or provided as two separate halves which can be secured by bolts, a band, or sliding, interlocking edges. The bumper rotates on a protective liner secured to the post. The protective liner is of a hardness to facilitate rotation and resist abrasion, adding to the piling's stiffness. There is a rotatable bumper in the prior art described as a boat mooring assembly comprising spring joints. The rotatable bumper alone has little capacity to absorb substantial impact energy and must be attached to the boat mooring assembly and dock. Prior art of marine fenders and fender systems teach a variety of construction, materials, and shapes to accommodate many types of fendering situations, but no prior art is heretofore suitable to replace used tires on existing monopiles and similar marine structures.
The inventor, a tool maker by trade, was approached in 2010 by Washington State Maritime Industry facility managers and administrators to consider an improved marine fender to replace used tires and recycled tire products on existing monopiles, dolphins, and over-water dock pilings. The improvement would be a fender that is simple to use and produce. Another consideration is that the fender installation would not require structural changes to existing marine structures. Preferred material is approved for use in marine habitats. The improved fender is cost-effective and environmentally-sound to install, inspect, maintain, or repair. Prototype construction of this marine fender was requested by Washington State Department of Ecology under contract #C1500137 in partnership with the Governor's Office for Maritime Industry and the Port of Seattle.
The claimed invention is marine fender which is specifically advantageous to compression-molded manufacturing using resilient material. One consideration for resilient material is ethylene propylene diene monomer or EPDM, which is a synthetic elastomer. The preferred material is a no-zinc formula EPDM that is currently approved for use in marine environments, such as a propriety EPDM produced by M & R Profiles of Seligenstadt, Germany, which the inventor has secured exclusive licensing rights for the purpose of manufacturing marine products. The proprietary EPDM complies with the European Union's REACH regulations. The proprietary EPDM has excellent properties of durability, UV resistance, tear resistance, and abrasion resistance.